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Re: [css-gcpm][css-color] device-cmyk() interaction with RGB-space colors.

From: Rik Cabanier <cabanier@gmail.com>
Date: Thu, 26 Sep 2013 12:32:47 -0700
Message-ID: <CAGN7qDD-=yoo3x8mDy58yYSouEvDdwg9MwTzDGPSB_LJpvYr1A@mail.gmail.com>
To: Brad Kemper <brad.kemper@gmail.com>
Cc: Henrik Andersson <henke@henke37.cjb.net>, Chris Lilley <chris@w3.org>, "Tab Atkins Jr." <jackalmage@gmail.com>, Simon Sapin <simon.sapin@exyr.org>, www-style list <www-style@w3.org>
It's weird that it works like that, right?
See attached png and PDF.
The intersection of a 100% cyan rect and a 100% magenta rect at 50% alpha
is 50% cyan and 50% magenta.


On Thu, Sep 26, 2013 at 7:47 AM, Brad Kemper <brad.kemper@gmail.com> wrote:

>
> > On Sep 26, 2013, at 4:35 AM, Henrik Andersson <henke@henke37.cjb.net>
> wrote:
> >
> > Rik Cabanier skriver:
> >>
> >> 5. How to handle content that has an RGB only operation (such as a
> >> colormatrix filter) during export to CMYK
> >
> > Wouldn't that particular filter make just as much sense as per channel
> > blend modes? After all, it is a per channel operation. Kinda.
> >
> > It would obviously need a dedicated configuration for other color
> > spaces, but the operation itself should make sense.
> >
> > Question is, has anyone actually tried using a color matrix on anything
> > besides RGB? Not counting shenanigans to setup the matrix to convert to
> > rgb before the main effect...
>
> I don't know much about the colormatrix filter, but for something like
> 'opacity', I don't see how you wouldn't convert cmyk to rgb before mixing
> channels. One is subtractive color and the other is additive.

alpha-cmyk.png
(image/png attachment: alpha-cmyk.png)

Received on Thursday, 26 September 2013 19:33:21 UTC

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